with TARGET, ENGLSL, ENGUSL and \( \bar{x} \) denoting the target
engineering value, the lower engineering specification limit, the upper
engineering specification limit and the sample mean, respectively.
This capability index combines both precision and unbiasedness.
The C_{pmk} statistic can have values from 0 to infinity with
values between 0.5 and 1 being typical.
The specification limits define the range within which a product is
considered acceptable (values outside this range indicate that a
product is defective).
Syntax:
LET <par> = CPMK <y>
<SUBSET/EXCEPT/FOR qualification>
where <y> is the response variable;
<par> is a parameter where the computed CPMK is stored;
and where the <SUBSET/EXCEPT/FOR qualification> is optional.
Examples:
LET A = CPMK Y1
LET A = CPMK Y1 SUBSET TAG > 2
Note:
The target and upper and lower specification limits must be specified
by the user as follows:
LET TARGET = <value>
LET LSL = <value>
LET USL = <value>
Note:
Dataplot statistics can be used in a number of commands. For
details, enter
Chen and Ding (2001), "A New Process Capability Index for Non-Normal
Distributions," International Journal of Quality & Reliability
Management, Vol. 18, No. 7, pp. 762-770.
Kaoru Ishikawa (1982), "Guide to Quality Control,"
Asian Productivity Organization, (chapter 13).
Applications:
Quality Control
Implementation Date:
2015/04
Program:
SKIP 25
READ FURNACE.DAT X1 X2 X3 Y
LET TARGET = 550
LET LSL = 460
LET USL = 660
LET A = CPMK Y
MULTIPLOT CORNER COORDINATES 5 5 95 95
MULTIPLOT 2 2
MULTIPLOT SCALE FACTOR 2
TITLE AUTOMATIC
CPMK PLOT Y X1
CPMK PLOT Y X2
CPMK PLOT Y X3
END OF MULTIPLOT
Date created: 07/31/2023
Last updated: 07/31/2023
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